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27 July 2010

Whooping cough: Back, with a vengeance

A few years ago, I went to India on a reporting trip. When I came back, I had a troublesome cough. I figured I'd picked up a bronchitis aggravated by New Delhi's smog-laden air, or by the dung smoke from the fires in the villages where I'd spent most of my time. The cough got worse instead of better. It was especially bad at night: I'd lie down to sleep and that would trigger a paroxysm. Sometimes I'd cough until I couldn't breathe. A few times, I vomited. Eventually my side began to hurt. (Months later, I discovered I'd cracked a rib.)

As a medical reporter, I spent most of my time around doctors and nurses, but I had a rule about never bothering them — first because I was pretty healthy, and second because no one wants to be the guy at the cocktail party who finds out someone's a doc and backs them into the corner of the buffet table. But one day, worn out by the spasms, I mentioned my symptoms to a friend. His eyes got big. He went and got a textbook.

I didn't have bronchitis. I had pertussis — whooping cough.

This made no sense, of course. Between a day job as Scary Disease Girl and a childhood spent moving between continents, I am pretty much the most vaccinated person on the planet. I'd had my full series of pertussis vaccinations as a child. Surely I was protected?

Actually, no — and unless you've had a booster, neither are you. The immunity created by the 5-dose childhood series wanes over time; by the age of 12, even fully vaccinated people are vulnerable to pertussis again. Since 2006, the Advisory Committee on Immunization Practices has been recommending a single additional pertussis (Tdap) booster for anyone between the ages of 11 and 64. That may seem like overkill — adult cases of pertussis in previously vaccinated people are often milder than the child version; after all, I survived my bout. But as with so many vaccines, the beneficiary here isn't just the adult taking the booster. Even more, it's the more vulnerable person to whom that adult might pass the disease: an elderly person with age-related immune decay; someone with a chronic disease; an infant too young to be vaccinated. In those people, the disease can and does kill — as it did an 18-day-old infant, Nelyn Baker, whom I wrote about in 2004.

Because vaccine immunity fades, pertussis is always with us: in good years, about 1,000 cases across the United States. Lately, though, we're in bad years. Pertussis cases are rising dramatically, in Alabama, Georgia, Arkansas, Texas, South Carolina, Michigan, Oregon and Ohio. The worst by far is California, where so far this year almost 1,500 cases of pertussis have been reported and another 700 are suspected — compared to 258 for the same time period in 2009.

"We are facing what could be the worst year for pertussis that this state has seen in more than 50 years,” Dr. Gilberto Chávez of the California Department of Public Health said last week in a statement put out by the agency's Center for Infectious Disease.

The worst news in this upsetting trend is this: We're doing it to ourselves. As far as anyone can tell, the rise in pertussis is not due to any change in the organism, or to any mysterious error among the manufacturers who make pertussis vaccines. It's due to vaccine refusal, to parents turning away from vaccines because they think the vaccines are more harmful than the diseases they prevent — or, more selfishly, because they think the wall of immunity created by other vaccinated children will protect their unimmunized ones.

That's an incorrect assumption, by the way. Work published last year by several scientists at Kaiser Permanente of Colorado found that unvaccinated children were 23 times more likely to contract pertussis than vaccinated ones. (Glanz, McClure, Magid et al., Pediatrics 2009, doi:10.1542/peds.2008-2150.) And yet, as numerous stories (LA Times, MedPage Today) have pointed out, California's epidemic has blossomed in a state that gives some of the most generous "personal belief exemptions" from vaccination — and the epidemic's worst hot spots neatly correlate with the most concentrated areas of vaccine refusal.

Pertussis is an awful disease. A child in the throes of a paroxysm sounds like nothing else on earth. Children turn blue, give themselves black eyes, die. We kept it down to manageable levels with the help of a vaccine. That we would willingly bring it back it is beyond belief.

(For a physician's take on pertussis, see this post by my fellow former SciblingPal MD. The CDC's information page on pertussis is hereand the National Network on Immunization Information explains the vaccination schedule here. H/t to the infectious-disease mailing list ProMED for starting me thinking.)

16 comments:

Well, Maryn, I absolutely sympathise. I went to India in 2007 and also came back with pertussis: very much like how you described it (although fortunately without the cracked rib).

The unfortunate thing was the healthcare system was quite unprepared to deal with it. I first sought help at an NHS walk-in clinic, where they diagnosed bronchitis and gave totally inappropriate antibiotics.

My GP didn't believe it was pertussis when I suggested that it might be. I only found out for sure that it was when I paid to see another GP privately and had my antibodies tested.

You're quite right: if the anti-vaxxers get their way, this sort of thing is going to become a lot more common.

The CDC has repeatedly issued press releases stating that vaccination rates have remained stable, and at a high level. The last press release was in 2009, which may be because the 2010 data isn't in yet. :)

The 'plummet' (as the NY Times put it) in vaccination rates seems to be a creation of the media, as opposed to, you know, fact.

I tried to look it up myself, and couldn't find rates any closer to now than 2006, so the CDC press release is the best source I have for this.

So I guess what I'm saying is that I'd like to see proof that vaccination rates are declining before I blame an increase in illness on it.

@Rose - Vaccination rates are so high throughout the US that statistical changes in the rate of vaccination will move extremely slowly (the actual CDC press release did note a change, but a statistically insignificant drop of 1%) particularly in places without .

A more effective way is to track how vaccine refusal rates may correlate with a surge in infections.

A cursory google turns up a JAMA article from 2006 relating to this: http://jama.ama-assn.org/cgi/content/abstract/296/14/1757

You say "As far as anyone can tell, the rise in pertussis is not due to any change in the organism," but is that true? There's some evidence that Pertussis is adapting to the vaccine. Have we looked at the Pt isolated from patients in the US to check?

http://www.cdc.gov/ncidod/eid/vol7no3_supp/mooi.htm"Adaptation may have allowed B. pertussis to remain endemic despite widespread vaccination and may have contributed to the reemergence of pertussis in The Netherlands."

http://jmm.sgmjournals.org/cgi/content/full/56/4/533"In Taiwan, as in other countries, an epidemic trend in pertussis has in part been attributed to the antigenic divergence in B. pertussis strains due to vaccine-driven selection as a result of using whole-cell pertussis vaccines for long periods"

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000904"B. pertussis is dynamic and is continuously evolving, suggesting that the bacterium may use gene loss as one strategy to adapt to highly immunized populations.

Rose, the last press release from the CDC was in Aug 2009: http://www.cdc.gov/media/pressrel/2009/r090827.htm

You need to read further than just the main title. For children aged 19 to 35 months, vaccination coverage for the main series was 76.1% in 2008 and 77.4% in 2007. The national goal is 80% for this age group and 90% for each vaccination overall. We're not hitting out goal.

This is also the National Average and doesn't show you the details since the problem is when small communities of people don't get vaccinated. The press release goes on to explain that the averages for states varies greatly: Montana was lowest at 59.2% and Massachusetts highest at 82.3%. See how it all changes depending on where you go? The proportion of children not vaccinated for 2008 was same as 2007, but remember that is a proportion and doesn't tell you what areas are seeing an increase and what areas are seeing a decrease.

Of course, this report is not perfect. Just look at the data collection: The data is collected doing a 'random' phone survey of households with children 19-35 months, as well as a mail survey of children's vaccination providers. For 2008, that's only 18,430 children with provider-reported vaccination records were included in this report. How many children are in the US?

The point, Rose, is not to make sure the national average stays stable. The point is to make sure that it does not decline in any region of the US and to make sure we get all areas (break it down to states if you want) at the 90% or higher rate. That's what everyone is worried about. Anything below that can't keep the spread of unwanted microbes in check. There is a lot of published research in top journals showing that you need to keep high vaccination rates in order to maintain the outbreak of (and ultimate goal of elimination of) microbes. Here's a good one for the infamous 2005 measles outbreak in Indiana (the largest documented outbreak since the CDC claimed that measles was eliminated in the US in 2000): http://www.nejm.org/doi/full/10.1056/NEJMoa060775 Note that outbreak happened five years after it was claimed to be 'eliminated'. And guess what the main reason for the outbreak was? Yep, it was from parents in that community not vaccinating their children.

I am from England but I contacted whooping cough (pertussis) as a 10 year old child. I was fully vaccinated and the doctors did not believe that I had it until I starting whooping violently in the doctor's office and then threw up.

My grandmother instantly recognised the symptoms as did an Austrian doctor friend. In Austria they call it the '100 day cough' and, true enough, it lasted a 100 days give or take.

After that experience I am always astonished by any parent who refuses to vaccinate their child. I was unlucky, but for the vast majority of people such illnesses are so easily avoided.

OBJECTIVES: To determine whether children who received recommended vaccines on time during the first year of life had different neuropsychological outcomes at 7 to 10 years of age as compared with children with delayed receipt or nonreceipt of these vaccines. METHODS: Publicly available data, including age at vaccination, from a previous VaccineSafety Datalink study of thimerosal exposure and 42 neuropsychological outcomes were analyzed. Vaccine receipt was defined as timely when each vaccine was received within 30 days of the recommended age. Associations between timeliness and each outcome were tested in univariate analyses. Multivariable regression models were constructed for further assessment of the impact of timeliness on neuropsychological outcomes after adjustment for potential confounders. Secondary analyses were performed on a subset of children with the highest and lowest vaccine exposures during the first 7 months of life. RESULTS: Timely vaccination was associated with better performance on 12 outcomes in univariate testing and remained associated with better performance for 2 outcomes in multivariable analyses. No statistically significant differences favored delayed receipt. In secondary analyses, children with the greatest vaccine exposure during the first 7 months of life performed better than children with the least vaccine exposure on 15 outcomes in univariate testing; these differences did not persist in multivariable analyses. No statistically significant differences favored the less vaccinated children. CONCLUSIONS: Timely vaccination during infancy has no adverse effect on neuropsychological outcomes 7 to 10 years later. These data may reassure parents who are concerned that children receive too many vaccines too soon.

My name is Andrew Prentice and I am a mathematics lecturer at Monash University in Australia. Aged 66 years. In early June this year a student came to my office to inform me that she had contracted Whooping Cough and needed special consideration for the upcoming math exam. Within a week I was coughing and whooping too! I had been feeling run down at the time of the student visit and my office window was closed, being winter time Downunder. So I was a sitting duck for contracting the disease. I am now on the mend (28 July) but still not back to par yet.

I had it too, a couple of years ago. Pretty awful. I just happened to read an article about the symptoms and recognized it. The amazing thing was I called my doctor to see if I should be treated because I was about to visit a family with small children and they said there really wasn't any treatment. Seemed pretty unconcerned, actually.

I think it is not helpful for people to suggest that families that opt out of vaccination programs are "stupid" to do so. The issue really is not so much whether or not data supports vaccinations or not, but whether or not the institutions in charge of creating, manufacturing, and distributing (and studying) the vaccines are trustworthy and/or acting in the public interest.It would be a much better use of activist's energies if they stopped trying to convince individual families to vaccinate, but instead focused on trying to bring the medical system into at least a semblance of accountability and freedom from conflict of interest.In the United States, it is becoming more and more clear that large for-profit interests are in control of the healthcare system. People see this trend, and decide that they do not want to put their trust in these corrupt institutions. They can simply dismiss data showing that vaccinations work by citing the numerous studies that have shown that there is a strong bias from researchers to come to conclusions in their published research that verifies their employer's predetermined expectations.Until these conflicts of interest are seriously addressed in the US and Canada, there will be more and more people choosing to opt out of vaccinations, and in fact to opt out of most corporate based medical care.

In addition to preventing you from passing on pertussis to others, getting the booster vaccine can benefit you directly. Even if you're a previously vaccinated adult, you can't count on getting a mild case. I have asthma, and I got pertussis as a teenager. I was *extremely* ill, and all the doctors could do for me was put me in an oxygen tent when I turned blue. I missed nearly 4 months of school, and my mom missed the same amount of work while she was taking care of me.

If you don't want to risk missing 4 months of your life, get the DTP booster. You need a tetanus booster anyway.

I contracted Pertussis this past August 2010. It is now, October 2, 2010, and I am still digging myself out of this. Seasoned physicians are missing the signs. As a result, adults like me, will board a plane, attend meetings, etc., infecting many along the way. I was able to figure out what I had, after sleuthing out the symptoms on the net, and listening to the sound of a cough on YouTube. A walk-in clinic treated me. However, upon re-contact with the clinic, to get help with the recovery phase - no one could offer any help or clinical advice.

Recovery can be tricky. The Pertussis organism produces toxins, one of which specifically targets the cells in the trachea and esophagus. I continue to have a raspy, barely there speaking voice, in the third month of recovery. If an adult required a normal speaking voice or vocal skills for their work, they could be out of work, for an extended period of time. Google: Pertussis toxin esophagus, and you'll see what I mean.

The only article I found, that finally and accurately addresses the adult "reservoir" for this bacteria, was in a Canadian newspaper. Sadly, I think most people are slow to embrace the notion, that teens and adults are/will be the population that transmits this to others. For an adult, it will possibly take months, to dig yourself out of the financial hole, created by lost work, trips to the doctor, medication (Tussinex with codine is $100.00 US for a small bottle), and weeks if not months of recovery. There appears to be a complete lack of physicians, who have hands on experience, with treating adults. The recovery phase is very difficult. I am in Orange County California. I called no less than 10 physicians, who promote themselves as infectious disease specialists. Yet none of them had any any experience with Pertussis. Seems as though a physician only needs to have experience with MRSA, to call themselves an "infectious disease specialist".

So very glad that you recovered nicely, and can share your experience. Hope other adults do the same.

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Maryn McKenna is an award-winning journalist and author and a recovering newspaper reporter. She writes about public health, medicine and food policy for national magazines and medical journals, and finds emerging diseases strangely exciting.

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